1. Field of the Invention
The invention relates to an apparatus and a method for triggering an emergency call in a motor vehicle.
2. Description of the Background Art
Motor vehicle emergency call terminal devices equipped with an emergency telephone unit are known in the art, whereby the emergency telephone unit establishes a call connection to an emergency center via a base station of a typical telecommunications network. Vehicle emergency call terminal devices are generally divided into two types: in the first type, an emergency button is pressed manually to output a call signal and in the second type a call signal is automatically output as a reaction to an output signal of an airbag sensor or a collision sensor. Some of the vehicle emergency call terminal devices of the first type are made to detect an unintended disconnection of a signal line from the emergency button, which results in the formation of an open electric circuit or a break in the electric circuit. In particular, terminal devices of this type comprise a control circuit, which monitors the pressing of the emergency button and an interruption of the signal line to the emergency button for performing the necessary operations. The connection of the emergency button to the control circuit is made via a switch when the emergency button is pressed.
DE 100 21 076 C2, which corresponds to U.S. Pat. No. 6,574,463, discloses an emergency call terminal device, which comprises an emergency call circuit, responsive to a request signal, to output an emergency call signal to a preselected emergency center and an emergency call switch connected to the emergency call circuit, whereby the emergency call switch is designed to be switched to an on-state and an off-state, whereby, if the emergency call switch is brought into the on-state, the call request signal is provided to the emergency call circuit. Further, the emergency call terminal device has an operating state signal producing circuit, which produces a first, second, third, and fourth operating state signal, different in voltage level from one another, in order to enable the emergency call circuit to differentiate the on-state, the off-state, a failure caused by a circuit break, and a failure caused by a short circuit. In this regard, the first operating state signal is produced when the emergency call switch is in the on-state; the second operating state signal is produced when the emergency call switch is in the off-state; the third operating state signal is produced when the switching failure caused by the circuit break results from a formation of an open circuit of the emergency call circuit caused by a disconnection of the emergency call circuit from the emergency call switch; and the fourth operating state signal is produced when the failure caused by a short circuit results from a formation of a short circuit of the emergency call switch.
DE 10 2008 038 492 A1 discloses a device for automatically making an emergency call, whereby the triggering event is, for example, a signal from an acceleration sensor. In this case, it is provided further that, if an emergency is detected such as, e.g., by an acceleration sensor, the intent of making an emergency call is indicated acoustically, optically, and haptically. If this intent is not countered by the driver within a short time of, for example, 5 seconds (e.g., by pressing a button on the mobile telecommunications unit), then the emergency call is made. If this is a fault detection, the driver responds and the emergency call is not made. Due to this possibility of a response by the driver, a lower detection threshold for the automatic emergency call can be selected and thereby an emergency can be recognized more reliably.
DE 10 2009 012 628 A1 discloses an arrangement for sending an emergency call with a module, which is located in a vehicle and is indispensable or necessary for vehicle functions, and a mobile telephone transceiver integrated into the module necessary for vehicle functions, whereby the module necessary for vehicle functions is designed to activate an emergency call via the integrated mobile telephone transceiver. In this regard, the emergency call is triggered manually and/or automatically after a specific event occurs. It is disclosed further here that the module necessary for vehicle functions is connected via communication lines to other modules, necessary for vehicle functions, of the vehicle electronics, whereby the specific event for making an emergency call is an interruption in the communication lines to the module necessary for vehicle functions.